blockchain: keep alternative blocks in LMDB

Alternative blocks are cleared on startup unless --keep-alt-blocks
is passed on the command line

4 files changed, 239 insertions, 1 deletions

diff --git a/src/blockchain_db/blockchain_db.h b/src/blockchain_db/blockchain_db.h
index 567be6a65..9cc8aaaaf 100644
--- a/src/blockchain_db/blockchain_db.h
+++ b/src/blockchain_db/blockchain_db.h
@@ -129,6 +129,15 @@ struct tx_data_t
 };
 #pragma pack(pop)
 
+struct alt_block_data_t
+{
+  uint64_t height;
+  uint64_t cumulative_weight;
+  uint64_t cumulative_difficulty_low;
+  uint64_t cumulative_difficulty_high;
+  uint64_t already_generated_coins;
+};
+
 /**
  * @brief a struct containing txpool per transaction metadata
  */
@@ -1528,8 +1537,45 @@ public:
    *
    * @param: sz the block size
    */
-
   virtual void add_max_block_size(uint64_t sz) = 0;
+
+  /**
+   * @brief add a new alternative block
+   *
+   * @param: blkid the block hash
+   * @param: data: the metadata for the block
+   * @param: blob: the block's blob
+   */
+  virtual void add_alt_block(const crypto::hash &blkid, const cryptonote::alt_block_data_t &data, const cryptonote::blobdata &blob) = 0;
+
+  /**
+   * @brief get an alternative block by hash
+   *
+   * @param: blkid the block hash
+   * @param: data: the metadata for the block
+   * @param: blob: the block's blob
+   *
+   * @return true if the block was found in the alternative blocks list, false otherwise
+   */
+  virtual bool get_alt_block(const crypto::hash &blkid, alt_block_data_t *data, cryptonote::blobdata *blob) = 0;
+
+  /**
+   * @brief remove an alternative block
+   *
+   * @param: blkid the block hash
+   */
+  virtual void remove_alt_block(const crypto::hash &blkid) = 0;
+
+  /**
+   * @brief get the number of alternative blocks stored
+   */
+  virtual uint64_t get_alt_block_count() = 0;
+
+  /**
+   * @brief drop all alternative blocks
+   */
+  virtual void drop_alt_blocks() = 0;
+
   /**
    * @brief runs a function over all txpool transactions
    *
@@ -1619,6 +1665,23 @@ public:
   virtual bool for_all_outputs(std::function<bool(uint64_t amount, const crypto::hash &tx_hash, uint64_t height, size_t tx_idx)> f) const = 0;
   virtual bool for_all_outputs(uint64_t amount, const std::function<bool(uint64_t height)> &f) const = 0;
 
+  /**
+   * @brief runs a function over all alternative blocks stored
+   *
+   * The subclass should run the passed function for each alt block it has
+   * stored, passing (blkid, data, blob) as its parameters.
+   *
+   * If any call to the function returns false, the subclass should return
+   * false.  Otherwise, the subclass returns true.
+   *
+   * The subclass should throw DB_ERROR if any of the expected values are
+   * not found.  Current implementations simply return false.
+   *
+   * @param std::function f the function to run
+   *
+   * @return false if the function returns false for any output, otherwise true
+   */
+  virtual bool for_all_alt_blocks(std::function<bool(const crypto::hash &blkid, const alt_block_data_t &data, const cryptonote::blobdata *blob)> f, bool include_blob = false) const = 0;
 
 
   //
diff --git a/src/blockchain_db/lmdb/db_lmdb.cpp b/src/blockchain_db/lmdb/db_lmdb.cpp
index 340434888..d17eebee4 100644
--- a/src/blockchain_db/lmdb/db_lmdb.cpp
+++ b/src/blockchain_db/lmdb/db_lmdb.cpp
@@ -194,6 +194,8 @@ namespace
  * txpool_meta      txn hash     txn metadata
  * txpool_blob      txn hash     txn blob
  *
+ * alt_blocks       block hash   {block data, block blob}
+ *
  * Note: where the data items are of uniform size, DUPFIXED tables have
  * been used to save space. In most of these cases, a dummy "zerokval"
  * key is used when accessing the table; the Key listed above will be
@@ -221,6 +223,8 @@ const char* const LMDB_SPENT_KEYS = "spent_keys";
 const char* const LMDB_TXPOOL_META = "txpool_meta";
 const char* const LMDB_TXPOOL_BLOB = "txpool_blob";
 
+const char* const LMDB_ALT_BLOCKS = "alt_blocks";
+
 const char* const LMDB_HF_STARTING_HEIGHTS = "hf_starting_heights";
 const char* const LMDB_HF_VERSIONS = "hf_versions";
 
@@ -1400,6 +1404,8 @@ void BlockchainLMDB::open(const std::string& filename, const int db_flags)
   lmdb_db_open(txn, LMDB_TXPOOL_META, MDB_CREATE, m_txpool_meta, "Failed to open db handle for m_txpool_meta");
   lmdb_db_open(txn, LMDB_TXPOOL_BLOB, MDB_CREATE, m_txpool_blob, "Failed to open db handle for m_txpool_blob");
 
+  lmdb_db_open(txn, LMDB_ALT_BLOCKS, MDB_CREATE, m_alt_blocks, "Failed to open db handle for m_alt_blocks");
+
   // this subdb is dropped on sight, so it may not be present when we open the DB.
   // Since we use MDB_CREATE, we'll get an exception if we open read-only and it does not exist.
   // So we don't open for read-only, and also not drop below. It is not used elsewhere.
@@ -1423,6 +1429,7 @@ void BlockchainLMDB::open(const std::string& filename, const int db_flags)
 
   mdb_set_compare(txn, m_txpool_meta, compare_hash32);
   mdb_set_compare(txn, m_txpool_blob, compare_hash32);
+  mdb_set_compare(txn, m_alt_blocks, compare_hash32);
   mdb_set_compare(txn, m_properties, compare_string);
 
   if (!(mdb_flags & MDB_RDONLY))
@@ -2241,6 +2248,50 @@ bool BlockchainLMDB::for_all_txpool_txes(std::function<bool(const crypto::hash&,
   return ret;
 }
 
+bool BlockchainLMDB::for_all_alt_blocks(std::function<bool(const crypto::hash&, const alt_block_data_t&, const cryptonote::blobdata*)> f, bool include_blob) const
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  check_open();
+
+  TXN_PREFIX_RDONLY();
+  RCURSOR(alt_blocks);
+
+  MDB_val k;
+  MDB_val v;
+  bool ret = true;
+
+  MDB_cursor_op op = MDB_FIRST;
+  while (1)
+  {
+    int result = mdb_cursor_get(m_cur_alt_blocks, &k, &v, op);
+    op = MDB_NEXT;
+    if (result == MDB_NOTFOUND)
+      break;
+    if (result)
+      throw0(DB_ERROR(lmdb_error("Failed to enumerate alt blocks: ", result).c_str()));
+    const crypto::hash &blkid = *(const crypto::hash*)k.mv_data;
+    if (v.mv_size < sizeof(alt_block_data_t))
+      throw0(DB_ERROR("alt_blocks record is too small"));
+    const alt_block_data_t *data = (const alt_block_data_t*)v.mv_data;
+    const cryptonote::blobdata *passed_bd = NULL;
+    cryptonote::blobdata bd;
+    if (include_blob)
+    {
+      bd.assign(reinterpret_cast<const char*>(v.mv_data) + sizeof(alt_block_data_t), v.mv_size - sizeof(alt_block_data_t));
+      passed_bd = &bd;
+    }
+
+    if (!f(blkid, *data, passed_bd)) {
+      ret = false;
+      break;
+    }
+  }
+
+  TXN_POSTFIX_RDONLY();
+
+  return ret;
+}
+
 bool BlockchainLMDB::block_exists(const crypto::hash& h, uint64_t *height) const
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
@@ -4062,6 +4113,110 @@ uint8_t BlockchainLMDB::get_hard_fork_version(uint64_t height) const
   return ret;
 }
 
+void BlockchainLMDB::add_alt_block(const crypto::hash &blkid, const cryptonote::alt_block_data_t &data, const cryptonote::blobdata &blob)
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  check_open();
+  mdb_txn_cursors *m_cursors = &m_wcursors;
+
+  CURSOR(alt_blocks)
+
+  MDB_val k = {sizeof(blkid), (void *)&blkid};
+  const size_t val_size = sizeof(alt_block_data_t) + blob.size();
+  std::unique_ptr<char[]> val(new char[val_size]);
+  memcpy(val.get(), &data, sizeof(alt_block_data_t));
+  memcpy(val.get() + sizeof(alt_block_data_t), blob.data(), blob.size());
+  MDB_val v = {val_size, (void *)val.get()};
+  if (auto result = mdb_cursor_put(m_cur_alt_blocks, &k, &v, MDB_NODUPDATA)) {
+    if (result == MDB_KEYEXIST)
+      throw1(DB_ERROR("Attempting to add alternate block that's already in the db"));
+    else
+      throw1(DB_ERROR(lmdb_error("Error adding alternate block to db transaction: ", result).c_str()));
+  }
+}
+
+bool BlockchainLMDB::get_alt_block(const crypto::hash &blkid, alt_block_data_t *data, cryptonote::blobdata *blob)
+{
+  LOG_PRINT_L3("BlockchainLMDB:: " << __func__);
+  check_open();
+
+  TXN_PREFIX_RDONLY();
+  RCURSOR(alt_blocks);
+
+  MDB_val_set(k, blkid);
+  MDB_val v;
+  int result = mdb_cursor_get(m_cur_alt_blocks, &k, &v, MDB_SET);
+  if (result == MDB_NOTFOUND)
+    return false;
+
+  if (result)
+    throw0(DB_ERROR(lmdb_error("Error attempting to retrieve alternate block " + epee::string_tools::pod_to_hex(blkid) + " from the db: ", result).c_str()));
+  if (v.mv_size < sizeof(alt_block_data_t))
+    throw0(DB_ERROR("Record size is less than expected"));
+
+  const alt_block_data_t *ptr = (const alt_block_data_t*)v.mv_data;
+  if (data)
+    *data = *ptr;
+  if (blob)
+    blob->assign((const char*)(ptr + 1), v.mv_size - sizeof(alt_block_data_t));
+
+  TXN_POSTFIX_RDONLY();
+  return true;
+}
+
+void BlockchainLMDB::remove_alt_block(const crypto::hash &blkid)
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  check_open();
+  mdb_txn_cursors *m_cursors = &m_wcursors;
+
+  CURSOR(alt_blocks)
+
+  MDB_val k = {sizeof(blkid), (void *)&blkid};
+  MDB_val v;
+  int result = mdb_cursor_get(m_cur_alt_blocks, &k, &v, MDB_SET);
+  if (result)
+    throw0(DB_ERROR(lmdb_error("Error locating alternate block " + epee::string_tools::pod_to_hex(blkid) + " in the db: ", result).c_str()));
+  result = mdb_cursor_del(m_cur_alt_blocks, 0);
+  if (result)
+    throw0(DB_ERROR(lmdb_error("Error deleting alternate block " + epee::string_tools::pod_to_hex(blkid) + " from the db: ", result).c_str()));
+}
+
+uint64_t BlockchainLMDB::get_alt_block_count()
+{
+  LOG_PRINT_L3("BlockchainLMDB:: " << __func__);
+  check_open();
+
+  TXN_PREFIX_RDONLY();
+  RCURSOR(alt_blocks);
+
+  MDB_stat db_stats;
+  int result = mdb_stat(m_txn, m_alt_blocks, &db_stats);
+  uint64_t count = 0;
+  if (result != MDB_NOTFOUND)
+  {
+    if (result)
+      throw0(DB_ERROR(lmdb_error("Failed to query m_alt_blocks: ", result).c_str()));
+    count = db_stats.ms_entries;
+  }
+  TXN_POSTFIX_RDONLY();
+  return count;
+}
+
+void BlockchainLMDB::drop_alt_blocks()
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  check_open();
+
+  TXN_PREFIX(0);
+
+  auto result = mdb_drop(*txn_ptr, m_alt_blocks, 0);
+  if (result)
+    throw1(DB_ERROR(lmdb_error("Error dropping alternative blocks: ", result).c_str()));
+
+  TXN_POSTFIX_SUCCESS();
+}
+
 bool BlockchainLMDB::is_read_only() const
 {
   unsigned int flags;
diff --git a/src/blockchain_db/lmdb/db_lmdb.h b/src/blockchain_db/lmdb/db_lmdb.h
index 4b46f081e..61a551476 100644
--- a/src/blockchain_db/lmdb/db_lmdb.h
+++ b/src/blockchain_db/lmdb/db_lmdb.h
@@ -67,6 +67,8 @@ typedef struct mdb_txn_cursors
   MDB_cursor *m_txc_txpool_meta;
   MDB_cursor *m_txc_txpool_blob;
 
+  MDB_cursor *m_txc_alt_blocks;
+
   MDB_cursor *m_txc_hf_versions;
 
   MDB_cursor *m_txc_properties;
@@ -87,6 +89,7 @@ typedef struct mdb_txn_cursors
 #define m_cur_spent_keys	m_cursors->m_txc_spent_keys
 #define m_cur_txpool_meta	m_cursors->m_txc_txpool_meta
 #define m_cur_txpool_blob	m_cursors->m_txc_txpool_blob
+#define m_cur_alt_blocks	m_cursors->m_txc_alt_blocks
 #define m_cur_hf_versions	m_cursors->m_txc_hf_versions
 #define m_cur_properties	m_cursors->m_txc_properties
 
@@ -108,6 +111,7 @@ typedef struct mdb_rflags
   bool m_rf_spent_keys;
   bool m_rf_txpool_meta;
   bool m_rf_txpool_blob;
+  bool m_rf_alt_blocks;
   bool m_rf_hf_versions;
   bool m_rf_properties;
 } mdb_rflags;
@@ -288,6 +292,12 @@ public:
   virtual bool update_pruning();
   virtual bool check_pruning();
 
+  virtual void add_alt_block(const crypto::hash &blkid, const cryptonote::alt_block_data_t &data, const cryptonote::blobdata &blob);
+  virtual bool get_alt_block(const crypto::hash &blkid, alt_block_data_t *data, cryptonote::blobdata *blob);
+  virtual void remove_alt_block(const crypto::hash &blkid);
+  virtual uint64_t get_alt_block_count();
+  virtual void drop_alt_blocks();
+
   virtual bool for_all_txpool_txes(std::function<bool(const crypto::hash&, const txpool_tx_meta_t&, const cryptonote::blobdata*)> f, bool include_blob = false, bool include_unrelayed_txes = true) const;
 
   virtual bool for_all_key_images(std::function<bool(const crypto::key_image&)>) const;
@@ -295,6 +305,7 @@ public:
   virtual bool for_all_transactions(std::function<bool(const crypto::hash&, const cryptonote::transaction&)>, bool pruned) const;
   virtual bool for_all_outputs(std::function<bool(uint64_t amount, const crypto::hash &tx_hash, uint64_t height, size_t tx_idx)> f) const;
   virtual bool for_all_outputs(uint64_t amount, const std::function<bool(uint64_t height)> &f) const;
+  virtual bool for_all_alt_blocks(std::function<bool(const crypto::hash &blkid, const alt_block_data_t &data, const cryptonote::blobdata *blob)> f, bool include_blob = false) const;
 
   virtual uint64_t add_block( const std::pair<block, blobdata>& blk
                             , size_t block_weight
@@ -452,6 +463,8 @@ private:
   MDB_dbi m_txpool_meta;
   MDB_dbi m_txpool_blob;
 
+  MDB_dbi m_alt_blocks;
+
   MDB_dbi m_hf_starting_heights;
   MDB_dbi m_hf_versions;
 
diff --git a/src/blockchain_db/testdb.h b/src/blockchain_db/testdb.h
index 6c97713d5..a32359c6c 100644
--- a/src/blockchain_db/testdb.h
+++ b/src/blockchain_db/testdb.h
@@ -155,6 +155,13 @@ public:
 
   virtual uint64_t get_max_block_size() override { return 100000000; }
   virtual void add_max_block_size(uint64_t sz) override { }
+
+  virtual void add_alt_block(const crypto::hash &blkid, const cryptonote::alt_block_data_t &data, const cryptonote::blobdata &blob) override {}
+  virtual bool get_alt_block(const crypto::hash &blkid, alt_block_data_t *data, cryptonote::blobdata *blob) override { return false; }
+  virtual void remove_alt_block(const crypto::hash &blkid) override {}
+  virtual uint64_t get_alt_block_count() override { return 0; }
+  virtual void drop_alt_blocks() override {}
+  virtual bool for_all_alt_blocks(std::function<bool(const crypto::hash &blkid, const alt_block_data_t &data, const cryptonote::blobdata *blob)> f, bool include_blob = false) const override { return true; }
 };
 
 }